Alajmi Ali Ahmed al-Atiri, the head of the brigade which captured Muammar Gaddafi's son Saif al-Islam, holds up a document as he addresses the media in Zintan June 9, 2012. A delegation for the International Criminal Court has been detained in Libya after one of its lawyers was found to be carrying suspicious documents for Saif al-Islam, a Libyan lawyer and a militia said on Saturday.

Nearly seven months after Libyan rebels cornered an exhausted Saif al-Islam Gaddafi in the remote Sahara Desert, the militia group holding him in custody has sparked an international row by arresting Saif’s defense lawyer for suspected spying. The act raises serious doubts over how much authority the government in Tripoli has over the country, as well as doubts about the fate of the most famous prisoner awaiting trial for all the Arab Spring’s revolutions.

The Zintan brigade -one of several armed groups who wield control over key areas of Libya–arrested Melinda Taylor, who is Australian, a seasoned defense attorney with the International Criminal Court (ICC). Also detained were three other ICC officials from The Hague. They were taken into custody mid-way through Taylor’s meeting last Thursday with Saif. When Taylor passed Saif a letter from one of his closest friends and former aides, Mohamed Ismail, the meeting was halted, and the ICC team arrested. “She was carrying letters from family and friends,” Ismail told TIME on Sunday, speaking by phone from Cairo. Asked what he’d written to his jailed friend, he said, “ask them.” Ismail said the prospect of a trial in Libya for Saif “is a joke. It would be a kangaroo court, and he would be executed,” he said. “He should have his day in court, and a court which is fair.”

That now seems unlikely any time soon. The head of the Zintan brigade, Alajami Ali Ahmed al-Atiri, told reporters on Saturday that Taylor had been arrested after Saif’s jailers found “spying and photography equipment on one of the delegation,” apparently referring to the camera and tape recorder carried by Taylor. One “document,” Atiri said, “incited Saif al-Islam to demand his trial at the ICC, to say that Libya has no laws, that he was being badly treated.” Australian Foreign Minister Bob Carr demanded Taylor’s immediate release and dispatched Australia’s ambassador to Italy, David Ritchie, to Tripoli on Sunday to negotiate.

But there are bigger issues at stake than Taylor’s freedom. Atiri’s accusation cuts to the heart of one of the most explosive issues in Libya these days: Who gets to try Saif. As the most crucial remnant from Muammar Gaddafi’s 42-year dictatorship, Saif is the sole person left alive to account for his father. He is thus a living target for decades of pent-up bitterness and rage among millions of Libyans. Saif’s impending trial is also seen among many Libyans as emblematic of who will be the real beneficiaries from last year’s bloody revolution: The front-line fighters, like those in Zintan, who fought a grueling seven-month battle against Gaddafi’s forces, or the government politicians in Tripoli, many of whom have returned from years of comfortable exile in the U.S. or Europe.

Staving off ICC demands to transfer Saif to the Hague for trial, Libyan government officials have assured the international court that the younger Gaddafi, 42, was about to be transferred to Tripoli, for trial by Libyan judges under internationally acceptable legal standards. Fathi Baja, head of the political and international affairs committee for Libya’s National Transitional Council told TIME in Tripoli in early May that Saif would be tried “in a couple of weeks in Tripoli.” Still, he admitted that negotiations were fraught. “I was in the meeting with the Zintan leaders,” Baja told me. “They were saying that the conditions for trial don’t exist in Tripoli. We say that this is the capital and we are a sovereign state.”

The ICC’s mandate is key to the West. It was part of the U.N. Security Council resolution that led to NATO’s bombing campaign against Gaddafi’s forces–the West’s only military intervention since the Arab Spring erupted 18 months ago. In June 2011, the ICC indicted Saif, his father, and Libya’s former intelligence chief Abdullah al-Senoussi, on crimes against humanity, for allegedly ordering Gaddafi’s forces to fire on unarmed demonstrators in eastern Libya during the early days of the revolution, in Feb. 2011, before the rebels morphed into an armed insurrection. Gaddafi is now dead, and Senoussi was arrested in Mauritania earlier this year after trying to sneak into that country. He looks unlikely to be returned to Libya for trail. Having garnered many fans among Western leaders during Gaddafi’s last years in power, Saif sealed his fate by siding with his father, vowing to crush the protesters “to the last man and woman and bullet.”

Aside from the infighting between Libya’s political rivals, Saif’s destiny has also raised deep-seated ideological questions over whether the new Libya will embody Western-style human rights. The court system remains largely non-functional. Instead, countless people have languished for months in detention under the control of disparate militia groups. “There is an ongoing problem of militias detaining people and the transitional government appearing not to be able to do anything about it,” Richard Dicker, head of Human Rights Watch’s international justice program, said by phone from New York on Sunday. “There are thousands of detained who are beyond the reach and authority of the government in Tripoli.”

With Libya still deeply unstable, international lawyers fear that Saif’s trial could be a major flashpoint for conflict if it unfolded inside the country. Dicker says he is haunted by Saddam Hussein’s trial in Baghdad, which ended with the ousted leader’s being hanged. “I was in Baghdad on the even of Saddam’s trial and two defense attorneys were gunned down in the street,” Dicker says. “At the end of the day it makes much more sense from Libya’s perspective to transfer Saif to the Hague. I understand the popular pressure, but if nothing else, the trial will be a security nightmare.” Likewise, the now-detained Taylor said in an interview in April that she had “real security concerns for a trial in Libya. Witnesses need to testify without fear of threats or intimidation.”

The specter of haphazard political trials for all those in detention–not just Saif–and of long jail stints with no trials at all, could affect the Arab Spring’s bloodiest conflict yet–Syria.

In contrast to Libya, the U.N. Security Council has not referred the Syrian massacres to the International Criminal Court for possible indictments, since Russia has blocked such attempts. Still, Dicker believes that as some Arab and Western politicians push for Libya-style military strikes in Syria, events in Libya–including the arrest of ICC officials–could affect how governments weigh their options against President Bashar Assad. “We’re seeing a ripple effect vis-a-vis Bashar -Assad,” he says.